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Electrochemistry

Question
CBSEENCH12006103

Calculate the molar conductivity at infinite dilution of acetic acid from the following data:
Λm (HCl) = 426 ohm–1 cm2 mol–1, Λm CH3COONa = 91 ohm–1 cm2 mol–1 and Λm(NaCl) = 126 ohm–1 cm2 mol–1.

Solution

Acetic acid is weak electrolyte than HCl and NaCl  which is strong electrolyte.
Acoording to kohlransch's law
λm(HCl) =λH+ +λCl- λm(NaCl) = λNa+ +λCl-λm(CH3COONa) =λCH3COO- +λNa+ λm(CH3COOH) =λCH3COO- +λH+ λm(CH3COOH) =λCH3COO- +λNa+-λNa+ +λCl-+λH+ +λCl- 

=91-126+426 =391

Ans.  391 ohm–1 cm2 mol-1